Abstract
A nanocrystalline quaternary Ni0.70-xCuxZn0.30Fe2O4 (x = 0.00, 0.05, 0.15, and 0.25)
ferrimagnetic thin film was deposited and studied utilizing advanced characterization
techniques, including XRD, Raman spectroscopy, FESEM, AFM, XPS, etc. The details of the
investigations made by these techniques into the structure, chemical environment, morphology,
physical properties, and sensing are presented in this chapter. Spray pyrolysis was used to
deposit quaternary ferrimagnetic thin films using metal nitrates as the starting material. The
cubic structure was revealed by XRD patterns. The peaks in the Raman spectra correspond to
the tetrahedral and octahedral sites supporting the formation of the cubic phase. The presence
of permitted compositional constituents in the XPS indicates phase-pure production. FESEM
images revealed some spherical agglomerations. The elemental composition was identified by
the presence of Ni, Cu, Zn, Fe, and O elements in the EDS pattern. The FESEM cross section
showed the deposition on the substrate, which is uniform and dense. The spherical shape, crackfree, and defect-free structure of deposited thin film system was observed by AFM. Contact
angle measurements showed the thin films were hydrophilic. The sensitivity among H2S, NO2
and NH3 gases was shown by H2S gas at an operating temperature of 200 C for a composition
of Ni0.65Cu0.05Zn0.30Fe2O4. The minimum detectable concentration was 20 ppm. With an
increase in H2S concentration, a linear improvement in the sensing response was seen.
Additionally, it was discovered that the response time shrank with an increase in H2S
concentration. At 50 ppm H2S, Ni0.65Cu0.05Zn0.30Fe2O4 has shown extremely high repeatability.